Pipe gripper actuated by guided yoke



y 1956 w.. M. MCCONNELL ET AL 2,747,445

PIPE GRIPPER ACTUATED BY GUIDED YOKE Original Filed Sept. 6, 1951 2Sheets-Sheet l INVENTORS William Afimard 111- 6 0121281! 60 2;; f0l212f2. V612 170F911.

\A/e/M; MM q-EW THEIR. ATTOZZZYEY' May 29, 1956 W. M. MCCON ET AL2,747,445

PIPE GRIPPER ACTUATED BY GUIDED YOKE Original Filed Sept. 6, 1951 2Sheets-Sheet 2 INVENTORS William /l[!/12QPQ'M @1ZI2CZ and Jolzlz 12.V01). HOF'll.

FHFIIZ ATTOHIVEY' United States Patent O PIPE GRIPPER ACTUATED BY GUIDEDYOKE William Mynard McConnell, McKeesport, and John R. Von Hofen,Pittsburgh, Pa., assignors to Taylor-Wilson Manufacturing Company,McKees Rocks, Pa., a corporation of Pennsylvania Original applicationSeptember 6, 1951, Serial No. 245,304, now Patent No. 2,707,876, datedMay 10, 1955. Divided and this application February 2-5, 1955, SerialNo. 490,588

2 Claims. (Cl. 81-172) This application is a division of our copendingapplication Serial No. 245,304 filed September 6, 1951, now Patent No.2,707,876.

This invention relates generally to grippers, and in particular, togrippers for pipe or tube placed in hydraulic testing machines. On someof these machines our grippers are a part of an automatic follow-upcontrol for maintaining a substantially constant space relationshipbetween the end of the pipe or tube and a head of the machine whichreceives the pipe or tube and makes a sealing engagement therewith.

Many automatic pipe-testing machines require grippers which have quickand positive action for extended periods of operation and which arerelatively inexpensive. To fulfill the foregoing requirements suchgrippers should have a simple and sturdy structure.

On pipe-testing machines where some of the grippers are a part of thefollow-up control described above, it is highly desirable that they beself-aligning with respect to the follow-up control and be lockedagainst accidental movement when not seizing a length of pipe.

Our invention provides a gripper which has a quick and positive actionand has a relatively simple and sturdy structure. In addition, oneembodiment of our invention has a self-aligning feature for use incombination with follov -up controls and has a locking feature forpreventing accidental movement thereof when not seizing a length ofpipe. Specifically, our gripper comprises a cage and a pair of jawspivoted therein. The jaws, when closed, are adapted to embrace a lengthof pipe. Mounted in the cage is a yoke having guided movement therein.Means actuates the yoke. The yoke has means adapted to engage the jawswhereby reciprocation of the yoke opens and closes the jaws.

In the accompanying drawings we have shown a preferred embodiment of ourinvention in which:

Figure l is a combined sectional view and elevation, as indicated by theline 11 of Figure 2, and shows our gripper mounted upon a pipe-testingmachine; and

Figure 2 is a partial side elevation showing our gripper as a part ofthe follow-up control shown and described in our copending applicationSerial No. 245,304 filed September 6, 1951, now Patent No. 2,707,876.

As shown in Figures 1 and 2, our gripper comprises a cage i suspendedbetween spaced side plates 2 and being slidable thereon. The spaced sideplates are a part of a hydraulic pipe-testing machine having a water end3 and a test head 4. The pipe-testing machine has, in addition, spacedtension rails 5 extending the full length of the machine and supportedon side frames 6. As shown in Figure 2, the spaced side plates 2 extendinwardly from the water end 3 and are aflixed thereto.

The cage 1 has flanges 7 on opposite sides thereof for 2,747,445Patented May 29, 1956 m a CC riding upon side plates 2. The cage is openat the top and has arms 8 depending from the bottom. A verticalfluid-pressure cylinder 9 is trunnioned in these arms. Pivoted upon apin 10 extending through the cage 1 parallel to the axis of the machineare semi-cylindrical clamping jaws 11.

Mounted on the piston of the cylinder 9 is a jawoperating yoke 12 whichhas links 13 pivoted to the upper end thereof on pins 14 located onopposite sides of the jaws 11. The cylinder 9 moves the yoke 12vertically in ways 15 formed in the corners of the cage.

Jaws 11 have cam surfaces 16 on their outer sides. Mounted adjacent theupper parts of the yoke 12 are rollers 17 on the pins 14. These rollersengage the cam surfaces 16 when the piston of the cylinder 9 is raisedthereby closing the jaws 11.

The links 13 have pin-and-slot connections '18 to the jaws 11, wherebyretraction of the piston of cylinder 9 pulls open the jaws 11.

To provide our gripper with the aforementioned selfaligning feature andthe locking feature, we make V-shaped openings 19 in the side plates 2.The side edges of these V-shaped openings have liners 20. Yoke 12 hasguide pins 21 extending laterally therefrom through slots 22 in the cageand between the liners 20. When the jaws 11 are closed to grip a lengthof pipe, the pins 21 are raised from the position shown in Figure 2. Inthe raised position these pins have suflicient clearance, with respectto the liners 20, to permit the desired amount of movement of thegripper on the side plates 2 to follow the shortening and lengthening ofa length of pipe while it is being tested. When the gripper is releasedfrom the pipe the pins 21 descend between liners 20 thereby centeringour gripper longitudinally on plates 2 so that it will be in correctposition for seizing the next length of pipe. When the yoke is in itslowered position, Figure 2, the gripper is locked against accidentalmovement which would operate valve 23. As shown in Figure 2, valve 23and push rod 24 connected to our gripper constitute a part of thefollow-up control mentioned previously herein.

From the foregoing it is clear that our invention has importantadvantages. In the first place, our gripper has a quick and positiveaction and a simple and sturdy structure. Hence, it is particularlysuitable for automatic pipe-testing machines which must continuallyoperate for extended periods. Furthermore, the simple structure lowersits cost of manufacture.

In the second place, our gripper has a self-aligning feature and alocking feature which prevents accidental movement thereof when notseizing a length of pipe. Thus, it is highly desirable for automatictesters where self-alignment after each test is essential. The lockingfeature is also highly desirable for it protects automatic follow-upcontrols such as those discussed above.

While a certain present preferred embodiment of the invention has beenherein described, it will be understood that it may be otherwiseembodied within the scope of the appended claims.

We claim:

1. A gripper adapted to seize a length of pipe comprising a cage mountedupon spaced plates and being slidable thereon, a pair of jaws pivotedtherein, said jaws being adapted, when closed, to embrace the length ofpipe, a yoke mounted in said cage and having guided movement therein,means for actuating said yoke, said yoke having means adapted to engagesaid jaws whereby reciprocation said yoke cooperating with said spacedplates to posi tion the cage at a predetermined location when said yokeis moved to open said jaws.

2. A gripper as defined by claim 1 characterized by said last-mentionedmeans including a pin extending laterally from said yoke through saidcage and converging surfaces on one of said plates adapted to be engagedby said pin. a

UNITED STATES PATENTS Parslow Apr. 2, 1918 Bower July 16, 1946 Webb Feb.14, 1950 Hoffman Jan. 12, 1954 Berkey et al. Sept. 7, 1954

